Method and system for producing fluoride gas and fluorine-doped glass or ceramics

ABSTRACT

The present invention relates generally to production of a fluoride gas and equivalents thereof, and fluorine-doped sodium silicate glass, glass ceramics, vitro ceramics and equivalents thereof. In one embodiment, the method includes providing a salt and an oxide in a reactor, heating the reactor to produce a vapor and the vitro ceramic and removing the vapor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/092,618, filed on Aug. 28, 2008, which is herein incorporated byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to a method and system forproducing fluoride gas and equivalents thereof, and fluorine-dopedglass, ceramics, vitro ceramic and equivalents thereof.

BACKGROUND OF THE INVENTION

During the production of high purity metals, for example silicon (Si) ortitanium (Ti), many by-products may be produced. One by-product inparticular is sodium fluoride (NaF). In current production of highpurity Si, NaF is typically packaged and sold. It is used forhydrofluoric acid (HF) production, water fluoridation, as an additive intooth paste, and the largest volume is for metallurgical fluxes orelectrolytes such as those used to produce aluminum metal. If the NaFproduced in very large quantities can be sold only for the lowest costapplication, then this results in lower credits and, thus, lower revenuefor the whole process.

Further adding to the raw material cost during the production of highpurity metals, for example Si or Ti, is the need of a large continuousstream of a source of the metal. For example, to produce high purity Sia large continuous source of fluorosilicic acid (H₂SiF₆) is needed.Typically, the H₂SiF₆ is purchased as a by-product from the fertilizerindustry. The present disclosure provides solutions to the issuesdescribed above.

SUMMARY OF THE INVENTION

In one embodiment, the present invention is directed towards producing avitro ceramic. In one embodiment, the method comprises providing a saltand an oxide in a reactor, heating said reactor to produce a vapor andsaid vitro ceramic and removing said vapor.

In one embodiment, the present invention is directed towards a methodfor recycling a salt during a production of a high purity metal toproduce a ceramic. The method comprises providing said salt produced asa by-product from said production of the high purity metal, providing anoxide, heating a mixture of said salt and said oxide in a reactor toproduce a gas and said ceramic and recycling said gas in said productionof said high purity metal.

In one embodiment, the present invention is directed towards a methodfor producing sodium silicate glass. The method comprises providingsodium fluoride (NaF) and silica sand (SiO₂) in a reactor, wherein saidNaF is provided as a by-product of a process to produce a high puritymetal, heating said reactor to produce a silicon tetrafluoride gas(SiF₄) and said sodium silicate glass doped with fluorine ions(Na₂SiO₃(F)) and recycling said SiF₄ back into said process to producesaid high purity metal.

BRIEF DESCRIPTION OF THE DRAWINGS

The teaching of the present invention can be readily understood byconsidering the following detailed description in conjunction with theaccompanying drawings, in which:

FIG. 1 illustrates one embodiment of a process flow diagram forproducing silicon tetrafluoride gas and fluorine-doped sodium silicateglass;

FIG. 2 illustrates one embodiment of the present invention as applied toa process for making silicon;

FIG. 3 illustrates a flow diagram of an exemplary process for producinghigh purity silicon by a melt process that may utilize the presentinvention;

FIG. 4 illustrates a flow diagram of one embodiment of a method forproducing a ceramic;

FIG. 5 illustrates a flow diagram of one embodiment of a method forrecycling a salt during a production of a high purity metal;

FIG. 6 illustrates a flow diagram of one embodiment of a method forproducing sodium silicate glass;

FIG. 7 illustrates an image of a fluorine doped silicate ceramicproduced from the present invention; and

FIG. 8 illustrates a second high magnification image of the fluorinedoped silicate ceramic produced from the present invention.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures.

DETAILED DESCRIPTION

The present invention provides a process for producing a vapor/gas andglass and/or ceramics. Hereinafter, the glass and/or ceramics may becollectively referred to as a ceramic. In one embodiment, the processbegins with an oxide and a salt. In one embodiment, the oxide may be ametallic oxide or a non-metallic oxide. In one embodiment, the salt maybe a fluoride salt. The fluoride salt, in a solid or molten form, and asolid metal oxide are heated in a reaction chamber to yield a firstproduct of fluoride gas and a second product of a solid fluorine dopedglass or ceramic with some impurities. A general equation of thereaction is shown below as Equation (1):

2yAF_(x)(s/l)+BOy(s)=BF2y(g)+2A_(2x)BO_(xa)(F)(s)+Impurities  Eq. (1)

In the above equation, A may be any Group I or II element or lanthanideelement, including lithium (Li), sodium (Na), potassium (K), magnesium(Mg), calcium (Ca), barium (Ba), strontium (Sr), lanthanum (La) orcerium (Ce). Thus, the salt may be lithium fluoride (LiF), sodiumfluoride (NaF), potassium fluoride (KF), magnesium fluoride (MgF₂),calcium fluoride (CaF₂), strontium fluoride (SrF₂), or barium fluoride(BaF₂) or fluorides of the lanthanides, such as for example, LaF₃ orCeF₃. In one embodiment, A is sodium and the salt is sodium fluoride. Inaddition, molten chlorides (not shown) may be mixed with the salt tohelp lower a melting point of the salt.

B in Equation (1) may be an element such as boron (B), aluminum (Al),gallium (Ga), indium (In), silicon (Si), germanium (Ge), titanium (Ti),zirconium (zr) or any transition metal. In one embodiment, B in Equation(1) is either Si or titanium Ti. It should be noted that the subscriptsor variables x, y and xa are a function of the elements used in Equation(1). That is, x may be an integer that represents the number of F atoms;y may be an integer that represents a number of O atoms and the like.The additional acceptable impurities may be determined by athermochemical model based on Gibbs energy minimization and predictedcomposition versus temperature.

In one embodiment, the above equation may be applied to a process forproducing a high purity semiconductor, such as for example, Si or Ge, ora metal, such as for example, Ti or Zr. For example, in the process forproducing high purity Si, a by-product of NaF is produced. In thisparticular example, a specific equation of the reaction when molten NaFis reacted with silicon dioxide (SiO₂) is shown below as Equation (2):

4+xNaF(s/l)+3SiO₂(s)+Impurities=SiF₄(g)+2Na₂SiO₃(Fx)(s)+Impurities  Eq.(2)

It should be noted that the “x” may vary depending on the number offluorine ions contained in the sodium silicate glass or ceramic. In oneembodiment, the silicon dioxide may be silica sand, or an equivalentsilica source. Notably, the sand may be unpurified sand that is readilyavailable. In the above exemplary reaction equation having the abovespecies and components, the impurities predicted by a thermochemicalmodel based upon Gibbs energy minimization and predicted compositionversus temperature may include, for example, NaF, SiOF₂ and Si₂OF₆ aswell as fluorides and oxyfluorides of impurity elements.

FIG. 1 illustrates one embodiment of a reaction 100 as described above.To drive the reaction 100 of the molten NaF with the SiO₂, the tworeactants may be heated in a reactor 102. In other words, the reactionequation shown in Eq. (2) may be considered endothermic up to sometemperature. At some point the entropy of the gas phase helps to drivethe reaction to generate silicon tetrafluoride (SiF₄) gas. The moltenNaF and SiO₂ may be heated to an approximate range of about 1000 degreesCelsius (° C.) to about 1500° C.

As more heat is applied to the reaction at higher temperatures, the moreSiF₄ vapor or gas is evolved. Hereinafter, SiF₄ vapor or gas may bereferred to collectively as SiF₄ gas. As the reaction temperatureapproaches approximately 1300° C., a vapor pressure of the SiF₄ gasproduct reaches over 200 Torrs. Consequently, the SiF₄ gas may beextracted out of the reactor at industrially reasonable rates usingliquid nitrogen condensation or a compressor.

The removed SiF₄ gas may contain impurities, although most of theimpurities remain in the liquid phase. As a result, in one embodiment,the SiF₄ gas may be purified. Any known purification process may be usedto remove the impurities from the SiF₄ gas such as distillation,condensation, adsorption, absorption, filtering, membranes, hybridtechnologies and the like. In one embodiment, a partial cooling of theSiF₄ stream to condense less volatile species and/or a condenserabsorber train may be used to purify the SiF₄ gas.

The purified SiF₄ gas may have many uses. In one embodiment, thepurified SiF₄ gas may be reacted with molten Na to produce Si, as willbe discussed in further detail below. In another embodiment, thepurified SiF₄ gas may be used to produce SiH₄ by reaction with a hydridespecies.

After the SiF₄ gas is removed, the remaining product may be a moltenmass that upon cooling becomes an amorphous silica based glass, ceramicor vitro ceramic. In one embodiment, the remaining product is a sodiumsilicate (Na₂SiO₃) glass or ceramic with embedded fluorine atoms(Na₂SiO₃(F)) and in some cases nano or microprecipitates of crystallineNaF. As the temperature of the reaction 100 goes higher to anapproximate range of 1200° C. to 1350° C., the SiF₄ gas evolutionincreases (as noted above) and a transparent glass is obtained havingresidual fluorine.

The fluorine doped sodium silicate glass or ceramic produced from thereaction of NaF and SiO₂ in Eq. (2) above is unexpectedly found to haveadvantageous properties that may have many industrial applications. Forexample, experiments on the sodium silicate glass with embedded fluorineatoms or ions and sodium ions have revealed that the conductivity of thefluorine ions within the sodium silicate vitro ceramic or glass is veryhigh at room temperature. The sodium ions are found to have similarlyhigh conductivity at room temperature. Thus, the fluorine doped sodiumsilicate glass with embedded fluorine atoms or ions and sodium ions maybe used as a fluoride ion conductive material or a sodium ion conductivematerial.

In addition, the fluorine doped sodium silicate glass or ceramic isobserved to be resistant to etching in hydrofluoric acid (HF) solutions.As a result, the fluorine doped sodium silicate glass or ceramic may beused to design new membranes, barriers, coatings, optical applicationsor new electrolytes for fuel cells or sensors. It should be noted thatthe new fluorine doped sodium silicate glass or ceramic produced by thenovel process disclosed herein may have additional applications that arewithin the scope of the present invention.

It should be noted that the above process is not limited to only siliconminerals such as silicon oxides. The above process may be extrapolatedto be used with other semiconductors such as Ge or metals such asaluminum (Al), gallium (Ga), indium (In) and transitional metalstitanium (Ti), vanadium (V), zirconium (Zr), niobium (Nb), molybdenum(Mo), tungsten (W) and tantalum (Ta), and even non-metals such as B.

The novel process described above may be used in various industrialprocesses to recycle materials or prevent waste. For example, FIG. 2illustrates a high level process flow diagram of the present inventionas applied within a process 200 for producing high purity Si. It shouldbe noted that the process 200 may be equally applied to a process forproducing Ti metal. One exemplary process for producing high puritysilicon is by using fluorosilicic acid (H₂SiF₆) as described in U.S.Pat. No. 4,442,082 issued to Angel Sanjurjo, U.S. Pat. No. 4,584,181,issued to Nanis, et al. and U.S. Pat. No. 4,590,043, issued to AngelSanjurjo, which are all hereby incorporated by reference.

A brief discussion of a process of producing high purity Si from H₂SiF₆will aid the reader on understanding a useful application of the presentinvention in one embodiment. An overall process 300 illustrated in FIG.3 consists of three major operations which encompass a series of steps.The first major operation includes the step of precipitation of sodiumfluorosilicate (Na₂SiF₆) from fluorosilicic acid (H₂SiF₆) followed bygeneration of silicon tetrafluoride gas (SiF₄) illustrated as a block ofsteps 310 in FIG. 3. Alternatively, the H₂SiF₆ may be obtained bytreating silica or silicates with hydrogen fluoride (HF). Theprecipitation of Na₂SiF₆ from H₂SiF₆ comprises a reaction equation asshown below by Eq. (3) and in sub-step 312 of FIG. 3.

H₂SiF₆(aq)+2NaF(c)=Na₂SiF₆(c)+2HF(aq)  Eq. (3)

The Na₂SiF₆ is filter dried in sub-step 314. Subsequently, the Na₂SiF₆is thermally decomposed in step 316 with heat. In one embodiment, theNa₂SiF₆ may be heated up to approximately 650° C. The reaction equationfor the thermal decomposition of Na₂SiF₆ is shown below by Eq. (4) andin sub-step 316 of FIG. 3.

Na₂SiF₆(c)+heat=SiF₄(g)+2NaF(c)  Eq. (4)

The second major operation comprises the reduction of the SiF₄ gas tosilicon (Si), preferably by sodium (Na) as illustrated by a block ofsteps 320 in FIG. 3. The reduction of the SiF₄ gas to silicon is shownbelow by Eq. (5) and in sub-step 322 of FIG. 3.

SiF₄(g)+4Na(s/l/g)=Si(s/l)+4NaF(s/l)  Eq. (5)

The third major operation involves the separation of Si from the mixtureof Si and molten sodium fluoride (NaF) as shown in a block of steps 330in FIG. 3. Further details of each of the above identified operationsare disclosed in U.S. Pat. Nos. 4,442,082, 4,584,181 and 4,590,043,which are hereby incorporated by reference. Moreover, the above stepsare merely provided as an example and are not to be considered limiting.

Previously, the NaF that was separated from the Si was packaged andsold. In some cases, the NaF could be transformed into HF, used forother metallurgical fluxing applications or for fluoridation in water ortooth paste. In some cases, it may be possible NaF can simply betransformed into calcium fluoride (CaF₂) and disposed of, but thatresults in higher raw material costs and lower revenue. Further addingto the raw material costs is a continuous large stream of H₂SiF₆ thatwas needed to produce SiF₄ gas, which continually fed the second majoroperation includes block of steps 320 of the above process 300 with theneeded SiF₄ gas.

In one embodiment, the present invention may be applied to the aboveprocess 300 to “close” the NaF stream rather than attempting to packageand sell the NaF, transform the NaF or dispose of the NaF. In doing so,the present invention also provides an unexpected result of producing asolid fluorine doped glass, ceramic or vitro ceramic with theadvantageous characteristics and benefits associated with the solidfluorine doped glass or ceramic described above.

One embodiment of this implementation is illustrated in FIG. 2. Forexample, the block of steps 320 and 330 are illustrated in a flowdiagram in FIG. 2. In one embodiment, molten Na is reacted with SiF₄ gasin a reactor 202. The Na is used to reduce the SiF₄ gas to silicon. Thereactor 202 may be any reactor suitable for carrying out the abovereaction. For example, the reactor may be any reactor vessel such as abatch reactor, a semicontinuous or continuous reactor or any reactorvessel as described in U.S. Pat. Nos. 4,442,082, 4,584,181 and4,590,043, which are hereby incorporated by reference. Reactionparameters for the above process of reducing the SiF₄ gas to Si with Naare provided in U.S. Pat. Nos. 4,442,082, 4,584,181 and 4,590,043, whichare hereby incorporated by reference.

The reaction of molten Na and SiF₄ gas produces molten NaF and Si. Themolten NaF is separated from the Si and removed from the reactor 202 andthen fed into a reactor 204. Silicon dioxide (SiO₂) (e.g. purified orunpurified silica sand) may be fed into the reactor 204 with the moltenNaF. As noted above, the reactor 204 may be any type of reactor suitablefor carrying out the reaction of molten NaF with SiO₂ within thetemperature ranges described above. For example, the reactor may be abatch reactor, a semicontinuous or continuous reactor and the like.

Subsequently, the reactor 204 may be heated to drive the reaction ofmolten NaF and SiO₂. In one embodiment, the molten NaF and SiO₂ may beheated to an approximate range of about 1000° C. to about 1500° C. Thereaction produces SiF₄ gas and sodium silicate glass or ceramic(Na₂SiO₃) with embedded fluorine ions and sodium ions, as discussedabove.

Notably, energy produced by the reaction carried out in reactor 202 mayhave a synergistic relationship with respect to the energy consumed bythe reaction carried out in reactor 204. For example, the reaction of Naand SiF₄ gas in reactor 202 is very exothermic. The reaction of NaF andSiO₂ in reactor 204 is endothermic. As a result, the energy and heatreleased by the reaction carried out in reactor 202 may be captured andused to heat the reaction carried out in reactor 204. As a result, noadditional energy may need to be applied from an external source to heatthe reaction of NaF and SiO₂. For example, although FIG. 2 illustratesthe use of two separate reactors 202 and 204, one skilled in the artwill recognize that in one embodiment a single reactor may be used. As aresult, the energy released by the reaction of Na and SiF₄ gas may beused to heat the reaction of NaF and SiO₂.

The SiF₄ gas may be removed from the reactor 204 and purified at block206 to remove any impurities, as described above. In one embodiment, acondenser absorber train may be used to purify the SiF₄ gas. Thepurified SiF₄ gas may then be fed back into the reactor 202 to reactwith Na to produce Si and NaF. Notably, the present invention mayreplace the need to perform the block of steps 310 in FIG. 3 byrecycling materials already within the processes 200 and 300. Thus, theprocess 200 may continuously recycle the molten NaF produced by thereduction of SiF₄ gas to Si by Na to re-generate more SiF₄.

In addition, the cost of raw materials is greatly lowered within theabove process for producing Si because the need for H₂SiF₆ and/or NaSiF₆is reduced only to an amount necessary for makeup needs. For example,only a small amount of makeup fluorine is needed to replace the fluorinelost in the fluorine doped sodium silicate glass or ceramic produced bythe reaction carried out in reactor 204. Moreover, due to the unexpectedproperties of the sodium silicate glass or ceramic with embeddedfluorine ions and sodium ions discussed above, the demand may be greaterthan the demand for NaF that was previously packaged and sold. As aresult, more revenue may also be recaptured with the above process dueto the valuable properties of the sodium silicate glass or ceramic withembedded fluorine ions and sodium ions.

It should be noted that FIG. 2 is only one particular example of aprocess that may reap benefits from the present invention. That is, itshould be recognized that the present invention may be usefully appliedto any process that requires recycling a halide salt to produce afluoride gas. For example, as noted above, the above process may beapplied to a process for producing titanium metal.

FIG. 4 illustrates a flow diagram of one embodiment of a method 400 forproducing a ceramic. In one embodiment, the method 400 may beimplemented as described above with reference to FIG. 1. The method 400begins at step 402.

At step 404, the method 400 provides a salt and an oxide in a reactor.For example, the salt may be a salt produced as a by-product from aproduction of a high purity metal as described above and illustrated inFIG. 3. The oxide may be a metallic oxide or a non-metallic oxide.

At step 406, the method 400 heats the reactor to produce a vapor and aceramic. For example, the vapor may be a SiF₄ gas and the ceramic may bea sodium silicate ceramic doped with fluorine ions. As noted above, thepresent invention may be applied to other metals. For example, the vaporcould be titaniumtetrafluoride (TiF₄) and the ceramic may be a calciumsilicate (CaSiO₃) ceramic doped with fluorine.

At step 408, the method 400 removes the vapor. In one embodiment, thegas may be removed and then recycled back into the process for producingthe high purity metal. For example, the recycling is illustrated in FIG.2 where SiF₄ is purified and recycled to react with Na to produce highpurity Si. The method 400 ends at step 410.

FIG. 5 illustrates a flow diagram of one embodiment of a method 500 forrecycling a salt during a production of a high purity metal to produce aceramic. In one embodiment the production of a high purity metal may besimilar to the process illustrated in FIG. 3. The method 500 begins atstep 502.

At step 504, the method 500 provides a salt produced as a by-productfrom a production of the high purity metal. As noted above, in oneexample, during the production of high purity Si, a by-product of NaFmay be produced.

At step 506, the method 500 provides an oxide. The oxide may be ametallic oxide or a non-metallic oxide. As described above withreference to FIG. 2, in one embodiment, the oxide may be a metal oxidethat is readily available, such as for example, purified or unpurifiedsilica sand or SiO₂.

At step 508, the method 500 heats a mixture of the salt and the oxide ina reactor to produce a gas and a ceramic. The mixture may be heated attemperatures near or even above the melting point of the metal. In oneembodiment, the gas may be a SiF₄ gas and the ceramic may be a sodiumsilicate ceramic doped with fluorine ions. As noted above, the presentinvention may be applied to other metals. For example, the vapor couldbe TiF₄ and the ceramic may be a CaSiO₃ ceramic doped with fluorine.

The method 500 includes an optional step 510 that recycles the vapor andgas in the production of the high purity metal. For example, therecycling is illustrated in FIG. 2 where SiF₄ is purified and recycledto react with Na to produce high purity Si. The method 500 ends at step512.

FIG. 6 illustrates a flow diagram of one embodiment of a method 600 forproducing sodium silicate glass. In one embodiment, the method 600 maybe implemented as described above with reference to FIG. 1. The method600 begins at step 602.

At step 604, the method 600 provides sodium fluoride (NaF) andunpurified silicon sand (SiO₂) in a reactor, wherein the NaF is providedas a by-product of a process to produce a high purity metal. Forexample, the NaF may be a by-product from a process producing a highpurity metal, such as Si, as illustrated in FIG. 3. The reactor may beany type of reactor as described above with reference to FIG. 2.

At step 606, the method 600 heats the reactor to produce a SiF₄ gas andthe sodium silicate glass doped with fluoride ions (Na₂SiO₃(F)). Forexample, the reactor may be heated within the temperature rangesdiscussed above in FIG. 2 with respect to reactor 102.

The method 600 includes an optional step 608 that recycles the SiF₄ intothe process to produce the high purity metal. For example, the recyclingis illustrated in FIG. 2 where SiF₄ is purified and recycled to reactwith Na to produce high purity Si. The method 600 ends at step 610.

EXAMPLES Example 1

A mixture of SiO₂ and NaF powders was loaded in a graphite crucible,which was placed inside a gas tight, water cooled, double wall quartzreactor. The graphite crucible and the powder mix were directly heatedby induction by means of a radio frequency (RF) coil powered by a RFpower supply. The system was then evacuated to eliminate any residualmoisture in the system, then heated to 1127° C. The pressure of the gasevolving was measured by a capacitance pressure gauge. The pressuremeasure was 60 torr.

Example 2

The experiment was performed as in Example 1, but the temperature was1227° C. The SiF₄ equilibrium pressure obtained was 200 torr. FIG. 7shows the resulting fluorine doped silicate glass/ceramic and FIG. 8shows a high magnification of the material.

Example 3

The experiment was performed as in Examples 1 and 2, but the temperaturewas 1327° C. The pressure obtained was 310 torr.

The thermochemical data for the species involved is well known so thatit is possible to estimate the expected pressure by using thermochemicalmodeling based on the minimization of Gibbs Free Energy programs. Theresults are summarized in Table 1 below.

TABLE 1 CALCULATED PARTIAL PRESSURES OF SPECIES OVER 4NaF + 3SiO₂ UNDERNEUTRAL CONDITIONS (atm) Species 1400 K 1500 K 1600 K 1700 K 1750 K Na3.39E−07 2.02E−06 9.52E−06 3.71E−05 6.88E−05 NaF 2.30E−03 8.16E−032.44E−02 6.31E−02 9.70E−02 SiF4 3.09E−02 1.15E−01 3.60E−01 9.79E−011.54E+00 SiOF2 3.59E−07 3.54E−06 2.61E−05 1.51E−04 3.35E−04 Si2OF68.44E−05 5.48E−04 2.81E−03 1.18E−02 2.26E−02 Na2Si2O5 6.42E−09 2.65E−081.21E−07 2.23E−08 3.79E−08 (1147)

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of a preferred embodiment shouldnot be limited by any of the above-described exemplary embodiments, butshould be defined only in accordance with the following claims and theirequivalents.

1. A method for producing a vitro ceramic, comprising: providing a saltand an oxide in a reactor; heating said reactor to produce a vapor andsaid vitro ceramic; and removing said vapor.
 2. The method of claim 1,wherein said salt comprises a metallic fluoride having a generalformula:AF_(X), wherein x is an integer representing a number of fluorine atoms,A comprises a Group I or II or Lanthanide element including at least oneof: lithium (Li), sodium (Na), potassium (K), magnesium (Mg), calcium(Ca), strontium (Sr), barium (Ba), lanthanum (La) or cerium (Ce); andwherein said oxide comprises a solid and has a general formula:BO_(y), wherein y is an integer representing a number of oxygen atoms, Bcomprises at least one of: boron (B), aluminum (Al), gallium (Ga),indium (In), silicon (Si), germanium (Ge), titanium (Ti), zirconium (Zr)or any transition metal.
 3. The method of claim 1, wherein said oxidecomprises silica sand.
 4. The method of claim 1, wherein said vaporcomprises a tetrafluoride vapor comprising a metal of said oxide.
 5. Themethod of claim 1, wherein said vitro ceramic comprises a first metaland a second metal, wherein said first metal is from said salt and saidsecond metal is from said oxide.
 6. The method of claim 5, wherein saidvitro ceramic is embedded with fluorine atoms or ions.
 7. The method ofclaim 1, wherein heating comprises heating said reactor at a temperatureof between a range of 1000 degrees Celsius (° C.) to about 1700° C. 8.The method of claim 1, wherein said heating comprises providing energyreleased from an exothermic reaction of said vapor and a metal of saidsalt to heat said reactor.
 9. A method for recycling a salt during aproduction of a high purity metal to produce a ceramic, comprising:providing said salt produced as a by-product from the production of saidhigh purity metal; providing an oxide; and heating a mixture of saidsalt and said oxide in a reactor to produce a gas and said ceramic. 10.The method of claim 9, further comprising: recycling said gas in saidproduction of said high purity metal.
 11. The method of claim 9, whereinsaid salt comprises a metallic fluoride having a general formula:AF_(x), wherein x is an integer representing a number of fluorine atoms,A comprises a Group I or II or Lanthanide element including at least oneof: lithium (Li), sodium (Na), potassium (K), magnesium (Mg), calcium(Ca), strontium (Sr), barium (Ba), lanthanum (La) or cerium (Ce); andwherein said oxide comprises a solid and has a general formula:BO_(y), wherein y is an integer representing a number of oxygen atoms, Bcomprises at least one of: boron (B), aluminum (Al), gallium (Ga),indium (In), silicon (Si), germanium (Ge), titanium (Ti), zirconium (Zr)or any transition metal.
 12. The method of claim 9, wherein said oxidecomprises silica sand.
 13. The method of claim 9, wherein said gascomprises a tetrafluoride gas comprising a metal of said oxide.
 14. Themethod of claim 9, wherein said ceramic comprises a first metal and asecond metal, wherein said first metal is from said salt and said secondmetal is from said oxide.
 15. The method of claim 14, wherein saidceramic is embedded with fluorine atoms or ions.
 16. The method of claim9, wherein heating comprises heating said reactor at a temperature ofbetween a range of 1000 degrees Celsius (° C.) to about 1700° C.
 17. Themethod of claim 9, wherein said heating comprises providing energyreleased from an exothermic reaction of said gas and a metal of saidsalt to heat said reactor.
 18. A method for producing sodium silicateglass, comprising: providing sodium fluoride (NaF) and silica sand(SiO₂) in a reactor, wherein said NaF is provided as a by-product of aprocess to produce a high purity metal; and heating said reactor toproduce a silicon tetrafluoride gas (SiF₄) and said sodium silicateglass doped with fluorine ions (Na₂SiO₃(F)).
 19. The method of claim 18,further comprising: recycling said SiF₄ back into said process toproduce said high purity metal.
 20. The method of claim 18, whereinheating comprises heating said reactor at a temperature of between arange of 1000 degrees Celsius (° C.) to about 1500° C.